tiff: declare var at begin of block

src/libImaging/TiffDecode.c

@@ -527,21 +527,21 @@ int ImagingLibTiffMergeFieldInfo(ImagingCodecState state, TIFFDataType field_typ
     // custom fields added with ImagingLibTiffMergeFieldInfo are only used for
     // decoding, ignore read_count;
     int read_count = 0;
-
     // we support writing single value, or a variable number of values
     int write_count = 1;
+    // whether the first value should encode the number of values.
+    int passcount = 0;
+
+    TIFFFieldInfo info[1];
+
     if (is_var_length) {
         write_count = -1;
     }
 
-    // whether the first value should encode the number of values.
-    int passcount = 0;
     if (is_var_length && field_type != TIFF_ASCII) {
         passcount = 1;
     }
-    const TIFFFieldInfo info[] = {
-        { key, read_count, write_count, field_type, FIELD_CUSTOM, 1, passcount, field_name }
-    };
+    info[0] = (TIFFFieldInfo) { key, read_count, write_count, field_type, FIELD_CUSTOM, 1, passcount, field_name };
     n = sizeof(info) / sizeof(info[0]);
 
     // Test for libtiff 4.0 or later, excluding libtiff 3.9.6 and 3.9.7